<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input id="one">+<input id="two"><span id="eq">=</span><span id="v"></span>
<script>
    var oneInput=document.getElementById('one')
    var twoInput=document.getElementById('two')
    var eq=document.getElementById('eq')
    var v=document.getElementById('v')

    eq.onclick=function () {
        var one=oneInput.value
        var two=twoInput.value
        v.innerText=(parseFloat(one)+parseFloat(two))
    }
</script>
</body>
</html>